I know that ATT has 4gLTE Now. It would be nice to have blackberry bold/torch or any model to connect playbook 4gLTE. Does it require to use bridge since playbook has 4g? I dont think it needs to connect? Now if I want carrier from sprint for blackberry bold 9930 and have playbook 4gLTE. How does it work because sprint doesnt provide 4g like ATT?

Will playbook speed 4g if i bridge blackberry bold to it if my carrier is Sprint? I am confusing.
I want to switch from att to sprint becuase cheap monthly but doesnt have 4g. Maybe I keep my att as well.